Nanotechnology Spotlight

A new process allows growing carbon nanotubes directly onto MEMS

(Nanowerk News) Researchers in Switzerland have successfully integrated carbon nanotubes (CNTs) directly into a polysilicon chip. This technique is opening the way towards NEMS and CNT based system integration and the synthesis and evaluation of mechanical nano-scale transducers based on CNTs.

(Left) Schematic of a MEMS with an integrated CNT (Source: ETH Zurich). (Right) Scanning electron microscopy image of an individual nanotube grown to span the gap between a polysilicon actuator and an anchor. (Reprinted with permission from Elsevier)

"With our novel process, individual or multiple tubes can be directly grown between movable posts and electrically connected. This way direct and reliable measurement techniques can be developed and used to accelerate research and evaluation of nanotube transducer properties."

CNTs are arguably the most studied nanomaterials in recent years due to their fascinating physical properties. Apart from their hardness and toughness they have demonstrated exceptionally high thermal conductivity, eventually exhibiting a property known as "ballistic conduction." This makes them ideal candidates for highly integrated electromechanical nanosystems (NEMS).

In developing NEMS major challenges still need to be overcome, foremost controlled and reproducilble integration of the tubes by local growth or self-assembly and the fundamental characterization of electromechanical effects in carbon nanotubes. Only then can CNT-based NEMS become a reality.

A research project in Hierold's group, called "Integrated nano transducers: fundamental characterization of electromechanical effects in carbon nanotubes" is focussing on exactly this problem area.